1. Field of the Invention
The present invention relates to an improved controlled release carrier system that can be incorporated into fabric care products, such as fabric softener, laundry detergents, tumble dryer sheets, and other fabric care products, that enhances deposition of active ingredients as well as fragrances onto fabric and which provides prolong release of active ingredients and fragrances from the dry laundered fabric over an extended period of time, or yields a high impact fragrance xe2x80x9cburstxe2x80x9d upon ironing the fabric.
2. Description of the Related Art
The household industry has searched for many years for ways to enhance the performance of fabric care products and make them more aesthetically pleasing for the consumers. Consumer acceptance of laundry products is determined not only by the performance achieved with these products but the aesthetics associated therewith. Fragrance is an important aspect of the successful fabric care products and they are being utilized, in addition to imparting an aesthetically pleasing odor, to convey to the consumer the product performance and effectiveness (i.e., the fabric is clean, freshly washed, etc.).
Fragrances are typically added to fabric care products to provide a fresh, clean impression for these products as well as the laundered fabric. While the fragrance does not add to the performance of fabric care products, it does make these products more aesthetically pleasing and the consumer has come to expect such products to have a pleasing odor. The fragrance plays a major, and often determining, role for the consumer in selecting and purchasing the fabric care product. Consumers are becoming increasingly educated and expect a high level of sophistication in their fabric care products. Many consumers would prefer for the fragrance present in these products, to be deposited on the fabric and remain there for an extended period of time to convey a lasting impression of freshness. Consumers are also interested in fabric care products that deposit high level of fragrance onto the fabric and release the fragrance upon ironing. Fragrance creation for fabric care products is restricted not only by considerations such as availability and cost, but also by compatibility of the fragrance ingredients to deposit onto the fabric and survive the wash and rise process. Furthermore, large amount of fragrance is being lost during the drying process, even when the fabrics are line dried. Practice has shown that when currently available fabric care products are used, a large fraction of the fragrance is lost during the rinse process due to the solubility of certain fragrance ingredients in aqueous washing compositions, and the fraction of the fragrance which was deposited, quickly evaporates, due to the volatility of fragrance ingredients.
Typical fabric care products such as laundry detergent compositions and fabric softener compositions contain 0.5% to 1% by weight fragrance in their formulations. U.S. Pat. No. 6,051,540, issued to the inventor of this disclosure, disclosure, discloses that in the course of the washing process wherein clothes are washed with the standard powdered laundry detergent, or fabric softener rinse, a very small fraction of the fragrance that is contained in these fabric care products is actually transferred to the clothes. Tests are described showing that the amount of fragrance that is left as a residue on the clothes can be as low as 1% of the original small amount of fragrance that is contained in these products formulation itself.
Attempts have been made to increase fragrance deposition onto fabric and to hinder or delay the release of the perfume so that the laundered fabric remains aeshtetically pleasing for a prolonged length of time. One approach used a carrier to bring the fragrance to the clothes. The carrier is formulated to contain a fragrance and to attach itself to the clothes during the washing cycle through particle entrainment or chemical change.
Perfumes have been adsorbed onto various materials such as silica and clay to deliver perfume in detergents and fabric softeners. U.S. Pat. No. 4,954,285 discloses perfume particles especially for use in dryer released fabric softening/antistatic agents. The perfume particles are formed, by adsorbing the perfume onto silica. The particles have a diameter of greater than about one micron. The particles can be used to reduce the shiny appearance of visible softener spots, which occasionally are present on fabrics treated with said fabric softening compositions and to maintain a relatively constant viscosity of the molten softening composition. The perfume particles are especially adapted for inclusion in dryer activated solid fabric softener compositions including coated particles of fabric softener, which are added to a detergent composition for use in the washing of fabrics. The compositions release softener to the fabrics in the dryer and improve the aesthetic character of any fabric softener deposits on fabrics. The perfume particles can also be admixed with detergent granules and can either be coated or uncoated. This system has the drawback that the fragrance oil is not sufficiently protected and is frequently lost or destabilized during processing.
U.S. Pat. Nos. 4,946,624, 5,112,688, and 5,126,061 disclose microcapsules, prepared by a coacervation process. The microcapsules have a complex structure in which there is a large central core of encapsulated material, preferably perfume, and the walls contain small wall inclusion particles of either the core material or some other material that can be activated to disrupt the wall. The microcapsules that are prepared by coacervation and contain perfume are incorporated into fabric softener compositions that have a pH of about 7 or less and which contain cationic fabric softener. The encapsulated perfume preferably does not contain large amounts of relatively water-soluble ingredients. Such ingredients are added separately to the fabric softener compositions. Ingredients that have high and low volatilities as compared to desired perfume, can either be added to, or removed from, the perfume to achieve the desired volatility. These type of controlled release system have the limitation of not working with all type of fragrance ingredients, especially not with fragrance ingredients that are relatively water-soluble and do not deposit into the fabric.
U.S. Pat. No. 4,402,856 describes the use of coacervation technique to create perfume particles for fabric care products composed of gelatin or a mixture of gelatin with gum arabic, carboxymethylcellulose and/or anionic polymers. The gelatin is hardened with a natural and/or synthetic tanning agent and with a carbonyl compound. According to the invention, the particles adhere to the fabric and are carried over to the dryer. Diffusion of the perfume out of the capsules occurs only in heat-elevated conditions of the dryer.
U.S. Pat. No. 4,152,272 teaches incorporating perfume into wax particles to protect the perfume during storage and through the laundry process. The perfume/wax particles are incorporated into an aqueous fabric conditioner composition. The perfume then diffuses from the particles onto the fabric in the heat-elevated conditions of the dryer.
U.S. Pat. No. 4,919,841 discloses wax encapsulated actives based on emulsion process for household applications including fabric. The process for preparing encapsulated active particles comprises the steps of: dispersing active materials in molten wax; emulsifying the active/wax dispersion in aqueous surfactant solution; quenching the capsules by cooling; and retrieving solidified capsules. The active materials may be selected from chlorine or oxygen bleaching agents, bleach precursors, enzymes, perfumes, fabric softening agents, and surfactants. The resultant capsules are in a form of dispersion (liquid) and have utility for cleaning compositions such as automatic dishwashing detergent formulations.
U.S. Pat. No. 5,246,603 describes composite microcapsules that are incorporated into a tumble drier article. The microcapsules comprise particles made of mixture of a wax material and a fragrance oil which are embedded in a water soluble polymer. The microcapsules have a diameter of less than about 100 microns and are useful for incorporation in tumble drier articles to control the release of fragrance in the drier and prevent loss of fragrance during processing and storage
U.S. Pat. No. 5,425,887 describes perfume capsules consisting of a water soluble natural or modified natural or synthetic polymer and perfume for a tumble dryer article. The perfume capsules are formed by mixing the polymer and the water to form a solution, adding the perfume to the solution to form an emulsified mixture and either spray drying or coacervating the emulsified mixture.
U.S. Pat. No. 6,042,792 issued to the inventor of this disclosure also describes an aqueous dispersion. A controlled, time-release microparticulate active and bioactive compositions (including perfuming compositions) for targeted delivery to services such as skin, hair and fabric and the environment proximate thereto is described in which the active and bioactive materials have a calculated log P values of between 1 and 8 (P being the n-octanol-water partition coefficient). Such compositions include the active or bioactive material in single phase, solid solution in a wax or polymer matrix also having coated thereon and/or containing a compatible surfactant. Also described are processes and apparatus for preparing such compositions and processes for using same. The fragrance formulation is selected and according this patent has the disadvantage of limiting the type of fragrances that can be used with the system.
U.S. Pat. Nos. 4,446,032 and 4,464,271 disclose liquid or solid fabric softener compositions comprising microencapsulated fragrance suspensions. The compositions contain sustained release fragrances that are prepared by combining non-confined fragrance Oils with encapsulated or physically entrapped fragrance oils. These combinations are fashioned so that the free fragrance oil or fragrance oil emulsion, are bound in a network of physically entrapped fragrance oil and suspending agent. The thixatropic pastes or free-flowing powders which result are products where the unconfined fragrance oil or unconfined fragrance oil emulsion, the xe2x80x9cencapsulatedxe2x80x9d or physically entrapped fragrance oil and suspending agent are held together by physical forces. The controlled release system comprise of a mixture of (i) a non-confined fragrance composition; (ii) one or more fragrance oils which are physically entrapped in one or more types of solid particles and (iii) a suspending agent such as hydroxypropyl cellulose, silica, xanthan gum, ethyl cellulose or combinations of the previously mentioned four substances; the non-confined fragrance substance, the entrapped fragrance oil and the suspension agent being premixed prior to the subsequent creation of the liquid or solid fabric softener compositions of matter.
Water soluble polymers have also been used to encapsulate fragrance oils. Such capsules have proved useful in releasing perfume in deodorants. However, such capsules have not been commercially successful in extended release of perfume from fabrics. U.S. Pat. No. 5,425,887 discloses an encapsulated perfume system in tumble dryer articles. The encapsulating material is a water-soluble natural or synthetic polymer with a molecular weight of less than about 300,000 that will release the perfume in response to moisture. Since these systems are water sensitive, these types of particles cannot be incorporated in aqueous fabric softener compositions.
U.S. Pat. Nos. 5,066,419, and 5,154,842 disclose coated perfume particles. The perfume particles comprise perfume dispersed within certain water-insoluble non-polymeric carrier materials and encapsulated in a protective shell by coating with a friable coating material. The coated particles allow for preservation and protection of perfumes, which are susceptible to degradation or loss in storage and in cleaning compositions. In use, the surface coating fractures and the underlying carrier/perfume particles efficiently deliver a large variety of perfume types to fabrics or other surfaces.
Several patents disclose the use of controlled release systems based on cyclodextrin complexes for fabric care applications, for example U.S. Pat. Nos. 5,094,761, 5,207,33, 5,232,612, 5,234,611, 5,236,615, 5,102,564, and 5,234,610. These patents disclose that fabric softening compositions, preferably in liquid form, for use in the rinse cycle of home laundry operations are improved by: (a) using certain protected water sensitive materials, especially particulate complexes of cyclodextrins and perfumes, which are protected in fabric softening compositions and/or detergent compositions, by imbedding the particulate complex in relatively high melting protective material that is substantially water-insoluble and, preferably, non-water-swellable and is solid at normal storage conditions, but which melts at the temperatures encountered in automatic fabric dryers (laundry dryers); (b) using soil release polymers to help suspend water-insoluble particles in aqueous fabric softening compositions; and/or (c) preparing the said protected particulate water sensitive materials (complexes) by melting the said high melting materials, dispersing the said particulate complexes, or other water sensitive material, in the molten high melting protective material and dispersing the resulting molten mixture in aqueous media, especially surfactant solution or aqueous fabric softener composition, and cooling to form small, smooth, spherical particles of the particulate complexes, or other water sensitive material, substantially protected by the high melting material. These systems have the disadvantage that the materials are expensive resulting in increased manufacturing costs.
U.S. Pat. Nos. 4,973,422, and 5,137,646 disclose perfume particles for use in cleaning and conditioning compositions. Perfume particles are disclosed comprising perfume dispersed within wax materials. The particles can be further be coated with a material that makes the particles more substantive to the surface being treated for example, fabric in the laundry process. Such materials help to deliver the particles to the fabric and maximize perfume release directly on the fabric. Generally, the coating materials are water-insoluble cationic materials. Cleaning and conditioning compositions comprising these perfume particles are also disclosed.
U.S. Pat. No. 6,024,943 discloses particles containing absorbed liquids and methods of making them. Perfume is absorbed within organic polymer particles, which have a further polymer at their exterior. The polymer incorporates free hydroxyl groups and serves to promote deposition of the particles from a wash or rinse liquor. The polymer may be part of an encapsulating shell, but more conveniently is used as a stabilizer during polymerization of the particles. Highly hydrolyzed polyvinyl alcohol is preferred. Particles containing organic polymer, which are insoluble in water, with liquid imbibed by the particles, the particles having at their exterior, a polymer which incorporates free hydroxy groups.
U.S. Pat. No. 5,476,660 discloses compositions to deposit an active substance on a target surface. The active substance is left on the surface after the product is rinsed off the surface. The preferred deposition is from compositions containing an anionic or nonionic active in the co-presence of an anionic surfactant. The compositions contain carrier particles having a zwitterionic or cationic surface and a plurality of outwardly protruding filaments containing charged organocarbyl groups. The term xe2x80x9czwitterionicxe2x80x9d employed in this patent means a mixture of cationic and anionic (not necessarily neutral); thus the surface of the zwitterionic particles, have both cationic and anionic groups (i.e., positively charged and negatively charged organocarbyl groups). The active substance is contained within the carrier particles. Examples of target surfaces are mammalian skin, hair or nails.
U.S. Pat. No. 6,051,540 discloses a method employing drum chilling for production fragrance-containing long lasting solid particle for incorporation into laundry detergents, fabric softener compositions, and drier-added fabric softener articles. The invention relates to encapsulating a pre-selected fragrance in a fat and a solid, non-ionic, surface active agent, from the group consisting of SPAN(copyright) surfactants for the purpose of imparting a fragrance to a laundry detergent composition, a fabric softener composition or a drier-added fabric softener. The invention also relates to a method of formulating a pre-selected fragrance formulation and a fat and surface-active agent carrier for the pre-selected fragrance formulation. The emphasis of U.S. Pat. No. 6,051,540 is in engineering the fragrance formulation and thus limiting the type of fragrances that can be used with the system. This patent also has the drawback that production of these particles, consists of a two step process (i.e., drum chilling and grind) which makes the production of this fragrance-particles to have high manufacturing costs.
U.S. Pat. No. 6,083,899 discloses fabric softener compositions that have enhanced softening benefits. The fabric softeners of consist of a fabric softener active in combination with a cationic charge booster. The cationic charge boosters disclosed are suitable for use with any fabric softener active, preferably with diester and diamide quaternary ammonium (DEQA) compounds. The invention only relates to the enhanced performance of the fabric softener actives as a result of incorporating the cationic charge boosters in these compositions. The invention does not disclose the use of cationic charge booster to deposit particles onto fabric.
It is desirable to provide a controlled delivery systems for fabric care products by maximizing the deposition of the system comprising the active ingredients onto the fabric. The key to maximizing deposition of the system, the nano-spheres of this invention, is optimizing particle size to ensure entrainment of the particles within the fabric fibers and having a sufficiently high cationic charge density on the particle surface to maximize ionic interaction between the particles and the fabric. There remains a need in the art for an efficient controlled delivery system, to effectively deposit active ingredients, as well as fragrances, onto fabric and for a method to xe2x80x9cboostxe2x80x9d the overall charge density of particles thereby providing enhanced deposition onto fabric.
The prior art of which applicant is aware does not set forth a fragrance controlled release system that can be incorporated in a fabric care products to enhance deposition of active ingredients, as well as fragrances, especially not for fragrance ingredients that are more soluble into the aqueous phase of the washing compositions and do not deposit onto the fabric. There is also a need for a fragrance carrier system, for fabric care products, that will allow using a wider range of fragrance ingredients that are currently not substantive on fabric and improved fragrance substantivity and longevity onto the laundered fabric. It is desirable to provide a control release system for overcoming these limitations. It is also desirable to provide a method using an efficient and economical process for effectively delivering a broad range of fragrance ingredients onto fabric and prolong fragrance release from the dry laundered fabric over an extended period of time, or yields a high impact fragrance xe2x80x9cburstxe2x80x9d upon ironing the fabric.
The present invention relates to an improved carrier system for fabric care products, such as powder laundry detergents, tumble dryer sheets, and other fabric care products, comprising a plurality of positively charged hydrophobic nano-spheres encapsulated in a water sensitive micro-sphere. A fragrance and active ingredients can be incorporated in the nano-sphere matrix, in the micro-sphere matrix, or in both the nano and micro-spheres matrices. The nano-sphere surface can have a high cationic charge density that improves fragrance deposition onto the laundered fabric. The high cationic charge density on the nano-sphere surface is created by incorporating a cationic fabric conditioning agent into the hydrophobic matrix of the nano-spheres, by incorporating a cationic charge xe2x80x9cboosterxe2x80x9d in the water sensitive micro-sphere matrix, or by using a cationic fabric conditioning agent in the nano-sphere matrix in conjunction with a cationic charge xe2x80x9cboosterxe2x80x9d in the micro-sphere matrix. The fragrance carrier system also provides controlled release or prolonged fragrance release from the dry laundered fabric over an extended period of time, or yields a high impact fragrance xe2x80x9cburstxe2x80x9d upon ironing the fabric.
In one embodiment, the present invention provides an improved fragrance carrier system for fabric care products, that has improved fragrance substantivity onto clothes which have been laundered and/or which have been treated with fabric softeners and/or which have been treated with rinse added, or drier-added fabric softener products. In the fabric care industry, the term xe2x80x9csubstantivityxe2x80x9d refers to the deposition of the fragrance on the clothes and the retention and perception of the fragrance on the laundered clothing and on the clothing treated with fabric care product. The cationic surface-active agents comprising the fragrance carrier system of the present invention allow a wide range of fragrances and fragrance ingredients to be compatible within the carrier composition and increase the substantivity of fragrances and fragrance ingredients that are currently not substantive on fabric. The fragrance-carrier system also provides prolonged fragrance release from the dry laundered fabric over an extended period of time, or yields a high impact fragrance xe2x80x9cburstxe2x80x9d upon ironing the fabric. A xe2x80x9cfragrance burstxe2x80x9d refers to immediate release of the fragrance. In addition, the production of the fragrance-carrier system utilizes minimum processing steps and is efficient and economical.
The carrier system of the present invention is a free-flowing, powder formed of solid hydrophobic positively charged nano-spheres comprising various active ingredients, as well as fragrances, that are encapsulated in a moisture sensitive micro-spheres, characterized by:
(i) protection of the active ingredients, as well as the volatile constituents of the fragrance, during storage, until needed;
(ii) moisture triggered release of the nano-spheres comprising the active ingredients, as well as the fragrance, in response to moisture (upon wash, in the dryer, etc.), and,
(iii) enhanced fragrance deposition onto fabric; and
(iv) prolonged fragrance release from the dry laundered fabric over an extended period of time; or
(v) yield high impact fragrance xe2x80x9cburstxe2x80x9d upon ironing the fabric.
The invention also provides a method for producing the multi component controlled release system of the present invention including active ingredients that comprise the steps of:
(i) incorporating cationic fabric conditioning agent, active ingredients, and a fragrance into a solid hydrophobic nano-spheres; and
(ii) forming an aqueous mixture comprising of one or more active agents, the nano-spheres, a cationic charge booster, and a water sensitive material, such as, starch derivatives, natural gums, polyvinyl alcohol, proteins, hydrocolloids, or mixture of thereof, and
(iii) spray drying the mixture to form a dry powder composition.
The invention further provides a process for producing the multi component controlled release system including the active ingredients and the fragrance that comprise the steps of:
(i) heating hydrophobic materials to a temperature above the melting point of the materials to form a melt;
(ii) dissolving or dispersing a cationic fabric conditioning agent into the melt;
(iii) dissolving or dispersing the fragrance and a first active agent into the melt;
(iv) dissolving or dispersing a second active agent, a cationic charge booster, and moisture sensitive materials, such as, starch derivatives, natural gums, polyvinyl alcohol, proteins, hydrocolloids, or mixture of thereof, in the aqueous phase;
(v) heating the composition to above the melting temperature of the hydrophobic material;
(vi) mixing the hot melt with the aqueous phase to form a dispersion;
(vii) high shear homogenization of the dispersion at a temperature above the melting temperature until a homogeneous fine dispersion is obtained having a sphere size of from about 1 micron to about 2 microns;
(viii) cooling the dispersion to ambient temperature; and
(ix) spray drying the emulsified mixed suspension to form a dry powder composition
The incorporation of spray dried nano-spheres comprising fragrances and other active agents encapsulated within a moisture sensitive matrix in fabric care products was found to enhance fragrance deposition onto fabric, and to extend the release rate of these fragrances and other active ingredients over an extended period of time. In an alternate embodiment, a controlled release composition is formed of hydrophobic nano-spheres incorporating active agents.
The invention also provides a fabric care product such as fabric softener, powder laundry detergents, tumble dryer sheets, and other fabric care products, comprising the multi component controlled release system of the present invention. Fabric laundered with powder laundry detergent or tumble dryer sheets comprising the multi component controlled release system of the present invention were observed to exhibit high level of fragrance (high odor intensity) in both the wet and the dry state and fragrance perception on the dry laundered fabric has been observed to be perceived over an extended period of time, i.e., two to three weeks.
The present invention addresses the foregoing need to increase the deposition of wide range of fragrances and fragrance ingredients onto fabric and prolong their release so that the laundered fabric remains aesthetically pleasing for an extended period of time by employing an advanced carrier system to bring the fragrance onto the clothes.
It is believed that the cationic charge groups on the nano-sphere surface become associated, in use of the composition, with the fabric and assists in adhering the nano-spheres onto fabric during the washing cycle through both sphere entrainment and electrostatic interactions to effectively deliver fragrance onto fabric and sustain fragrance release rate. The hydrophobic matrix sustains the diffusion rate of the fragrance through the nano-spheres and enables the fragrance to be released from the dry laundered fabric over an extended period of time, or during heat treatment such as ironing.
The multi-component controlled release system of the present invention can comprise from about 1% to about 50% by weight hydrophobic matrix, from about 1% to about 50% by weight water sensitive matrix, from about 0% to about 10% by weight cationic charge booster, from about 0.01% to about 10% by weight cationic fabric softening agents, and from about 1% to about 50% by weight fragrance. The micro-sphere have an average sphere size in the range from about 20 microns to about 100 microns, the nano-sphere have an average sphere size in the range from about 0.01 micron to about 5 microns and having a melting point in the range from about 30 degrees C. to about 100 degrees C. The micro-spheres can be incorporated into any fabric care products, preferably in powder laundry detergent, fabric softener, or tumble dryer sheet compositions.
The carrier system of the present invention can be incorporated in tumble-dryer sheets as well as dry granular or powder fabric care compositions and provide long-term storage stability.